Chair seat and back



FIG. 1 is a front view of a chair seat and back showing our new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof; and,

FIG. 5 is a top view thereof. 

The ornamental design for a chair seat and back, as shown. 